1. Technical Field
Embodiments of the present invention relate to an image forming apparatus such as a copier, printer, facsimile machine, a multifunctional machine having functions of the copier, printer, and facsimile machine, and so forth, a sheet positioning device that supplies recording media for producing prints and copies, and a method of sheet positioning used for the sheet positioning device that is includable in the image forming apparatus.
2. Related Art
Known image forming apparatuses such as copiers and printers employ a sheet supplying device having a technique in which a pair of side fences automatically slides to sandwich and contact lateral edges of a sheet.
For example, Japanese Patent Application Publication Nos. 2011-162355 (JP-2011-162355-A) and 2012-062127 (JP-2012-062127-A) disclose sheet positioning devices (paper storage devices) in which a pair of side fences (side fences) is disposed at both lateral ends of a sheet setting member (table or surface). When a sheet is placed on the sheet setting member, a controller starts driving a drive motor to slide the pair of side fences to sandwich the sheet at both lateral ends. When contact between the pair of side fences and the sheet is detected, the controller stops driving the drive motor to stop moving the side fences. Such an action to regulate the pair of side fences to sandwich both lateral edges of the sheet can reduce or to eliminate skewing of the sheet when feeding the sheet forward for printing, lateral mispositioning of the sheet, and wrinkling of the sheet.
Further, with the configuration in which the pair of side fences slides automatically, the sheet can be aligned more correctly compared to aligning the sheet by sliding the pair of side fences manually.
However, known sheet supplying devices have sometimes caused the pair of side fences to be out of a target position due to inertia when the controller stops driving the drive motor after a detector (or detectors) detects contact of the sheet and the pair of side fences in the lateral direction. Further, sheets of different thickness or a significant change in the number of sheets set on the sheet setting member prevents the detector from detecting contact of the sheet and the pair of side fences in the lateral direction correctly. As a result, the sheet is skewed when fed, lateral mispositioning, wrinkling thereon.